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        <h1>
          <span class="m-breadcrumb"><a href="namespacetf.html">tf</a>::<wbr/></span>Subflow <span class="m-thin">class</span>
        </h1>
        <p>class to construct a subflow graph from the execution of a dynamic task</p>
        <nav class="m-block m-default">
          <h3>Contents</h3>
          <ul>
            <li>
              Reference
              <ul>
                <li><a href="#base-classes">Base classes</a></li>
                <li><a href="#pub-methods">Public functions</a></li>
              </ul>
            </li>
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<p><a href="classtf_1_1Subflow.html" class="m-doc">tf::<wbr />Subflow</a> is a derived class from <a href="classtf_1_1Runtime.html" class="m-doc">tf::<wbr />Runtime</a> with a specialized mechanism to manage the execution of a child graph. By default, a subflow automatically <em>joins</em> its parent node. You may explicitly join or detach a subflow by calling <a href="classtf_1_1Subflow.html#a59fcac1323e70d920088dd37bd0be245" class="m-doc">tf::<wbr />Subflow::<wbr />join</a> or <a href="classtf_1_1Subflow.html#acfdedc7e9676126e9a38ecf7b5a37864" class="m-doc">tf::<wbr />Subflow::<wbr />detach</a>, respectively. The following example creates a taskflow graph that spawns a subflow from the execution of task <code>B</code>, and the subflow contains three tasks, <code>B1</code>, <code>B2</code>, and <code>B3</code>, where <code>B3</code> runs after <code>B1</code> and <code>B2</code>.</p><pre class="m-code"><span class="c1">// create three static tasks</span>
<span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">A</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;A&quot;</span><span class="p">);</span>
<span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">C</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;C&quot;</span><span class="p">);</span>
<span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">D</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;D&quot;</span><span class="p">);</span>

<span class="c1">// create a subflow graph (dynamic tasking)</span>
<span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">B</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([]</span><span class="w"> </span><span class="p">(</span><span class="n">tf</span><span class="o">::</span><span class="n">Subflow</span><span class="o">&amp;</span><span class="w"> </span><span class="n">subflow</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w">  </span><span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">B1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">subflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;B1&quot;</span><span class="p">);</span>
<span class="w">  </span><span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">B2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">subflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;B2&quot;</span><span class="p">);</span>
<span class="w">  </span><span class="n">tf</span><span class="o">::</span><span class="n">Task</span><span class="w"> </span><span class="n">B3</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">subflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;B3&quot;</span><span class="p">);</span>
<span class="w">  </span><span class="n">B1</span><span class="p">.</span><span class="n">precede</span><span class="p">(</span><span class="n">B3</span><span class="p">);</span>
<span class="w">  </span><span class="n">B2</span><span class="p">.</span><span class="n">precede</span><span class="p">(</span><span class="n">B3</span><span class="p">);</span>
<span class="p">}).</span><span class="n">name</span><span class="p">(</span><span class="s">&quot;B&quot;</span><span class="p">);</span>

<span class="n">A</span><span class="p">.</span><span class="n">precede</span><span class="p">(</span><span class="n">B</span><span class="p">);</span><span class="w">  </span><span class="c1">// B runs after A</span>
<span class="n">A</span><span class="p">.</span><span class="n">precede</span><span class="p">(</span><span class="n">C</span><span class="p">);</span><span class="w">  </span><span class="c1">// C runs after A</span>
<span class="n">B</span><span class="p">.</span><span class="n">precede</span><span class="p">(</span><span class="n">D</span><span class="p">);</span><span class="w">  </span><span class="c1">// D runs after B</span>
<span class="n">C</span><span class="p">.</span><span class="n">precede</span><span class="p">(</span><span class="n">D</span><span class="p">);</span><span class="w">  </span><span class="c1">// D runs after C</span></pre>
        <section id="base-classes">
          <h2><a href="#base-classes">Base classes</a></h2>
          <dl class="m-doc">
            <dt>
              class <a href="classtf_1_1FlowBuilder.html" class="m-doc">FlowBuilder</a>
            </dt>
            <dd>class to build a task dependency graph</dd>
            <dt>
              class <a href="classtf_1_1Runtime.html" class="m-doc">Runtime</a>
            </dt>
            <dd>class to include a runtime object in a task</dd>
          </dl>
        </section>
        <section id="pub-methods">
          <h2><a href="#pub-methods">Public functions</a></h2>
          <dl class="m-doc">
            <dt>
              <span class="m-doc-wrap-bumper">void <a href="#a59fcac1323e70d920088dd37bd0be245" class="m-doc">join</a>(</span><span class="m-doc-wrap">)</span>
            </dt>
            <dd>enables the subflow to join its parent task</dd>
            <dt>
              <span class="m-doc-wrap-bumper">void <a href="#acfdedc7e9676126e9a38ecf7b5a37864" class="m-doc">detach</a>(</span><span class="m-doc-wrap">)</span>
            </dt>
            <dd>enables the subflow to detach from its parent task</dd>
            <dt>
              <span class="m-doc-wrap-bumper">void <a href="#a540be503df4621be3e8342b99b1729a0" class="m-doc">reset</a>(</span><span class="m-doc-wrap">bool clear_graph = true)</span>
            </dt>
            <dd>resets the subflow to a joinable state</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#ac3805e898b6a55b6e5173c74c5555e57" class="m-doc">joinable</a>(</span><span class="m-doc-wrap">) const -&gt; bool <span class="m-label m-flat m-success">noexcept</span></span>
            </dt>
            <dd>queries if the subflow is joinable</dd>
          </dl>
        </section>
        <section>
          <h2>Function documentation</h2>
          <section class="m-doc-details" id="a59fcac1323e70d920088dd37bd0be245"><div>
            <h3>
              <span class="m-doc-wrap-bumper">void tf::<wbr />Subflow::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a59fcac1323e70d920088dd37bd0be245" class="m-doc-self">join</a>(</span><span class="m-doc-wrap">)</span></span>
            </h3>
            <p>enables the subflow to join its parent task</p>
<p>Performs an immediate action to join the subflow. Once the subflow is joined, it is considered finished and you may not modify the subflow anymore.</p><pre class="m-code"><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](</span><span class="n">tf</span><span class="o">::</span><span class="n">Subflow</span><span class="o">&amp;</span><span class="w"> </span><span class="n">sf</span><span class="p">){</span>
<span class="w">  </span><span class="n">sf</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){});</span>
<span class="w">  </span><span class="n">sf</span><span class="p">.</span><span class="n">join</span><span class="p">();</span><span class="w">  </span><span class="c1">// join the subflow of one task</span>
<span class="p">});</span></pre><p>Only the worker that spawns this subflow can join it.</p>
          </div></section>
          <section class="m-doc-details" id="acfdedc7e9676126e9a38ecf7b5a37864"><div>
            <h3>
              <span class="m-doc-wrap-bumper">void tf::<wbr />Subflow::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#acfdedc7e9676126e9a38ecf7b5a37864" class="m-doc-self">detach</a>(</span><span class="m-doc-wrap">)</span></span>
            </h3>
            <p>enables the subflow to detach from its parent task</p>
<p>Performs an immediate action to detach the subflow. Once the subflow is detached, it is considered finished and you may not modify the subflow anymore.</p><pre class="m-code"><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](</span><span class="n">tf</span><span class="o">::</span><span class="n">Subflow</span><span class="o">&amp;</span><span class="w"> </span><span class="n">sf</span><span class="p">){</span>
<span class="w">  </span><span class="n">sf</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){});</span>
<span class="w">  </span><span class="n">sf</span><span class="p">.</span><span class="n">detach</span><span class="p">();</span>
<span class="p">});</span></pre><p>Only the worker that spawns this subflow can detach it.</p>
          </div></section>
          <section class="m-doc-details" id="a540be503df4621be3e8342b99b1729a0"><div>
            <h3>
              <span class="m-doc-wrap-bumper">void tf::<wbr />Subflow::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a540be503df4621be3e8342b99b1729a0" class="m-doc-self">reset</a>(</span><span class="m-doc-wrap">bool clear_graph = true)</span></span>
            </h3>
            <p>resets the subflow to a joinable state</p>
            <table class="m-table m-fullwidth m-flat">
              <thead>
                <tr><th colspan="2">Parameters</th></tr>
              </thead>
              <tbody>
                <tr>
                  <td style="width: 1%">clear_graph</td>
                  <td>specifies whether to clear the associated graph (default <code>true</code>)</td>
                </tr>
              </tbody>
            </table>
<p>Clears the underlying task graph depending on the given variable <code>clear_graph</code> (default <code>true</code>) and then updates the subflow to a joinable state.</p>
          </div></section>
          <section class="m-doc-details" id="ac3805e898b6a55b6e5173c74c5555e57"><div>
            <h3>
              <span class="m-doc-wrap-bumper">bool tf::<wbr />Subflow::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#ac3805e898b6a55b6e5173c74c5555e57" class="m-doc-self">joinable</a>(</span><span class="m-doc-wrap">) const <span class="m-label m-success">noexcept</span></span></span>
            </h3>
            <p>queries if the subflow is joinable</p>
<p>This member function queries if the subflow is joinable. When a subflow is joined or detached, it becomes not joinable.</p><pre class="m-code"><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](</span><span class="n">tf</span><span class="o">::</span><span class="n">Subflow</span><span class="o">&amp;</span><span class="w"> </span><span class="n">sf</span><span class="p">){</span>
<span class="w">  </span><span class="n">sf</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){});</span>
<span class="w">  </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o">&lt;&lt;</span><span class="w"> </span><span class="n">sf</span><span class="p">.</span><span class="n">joinable</span><span class="p">()</span><span class="w"> </span><span class="o">&lt;&lt;</span><span class="w"> </span><span class="sc">&#39;\n&#39;</span><span class="p">;</span><span class="w">  </span><span class="c1">// true</span>
<span class="w">  </span><span class="n">sf</span><span class="p">.</span><span class="n">join</span><span class="p">();</span>
<span class="w">  </span><span class="n">std</span><span class="o">::</span><span class="n">cout</span><span class="w"> </span><span class="o">&lt;&lt;</span><span class="w"> </span><span class="n">sf</span><span class="p">.</span><span class="n">joinable</span><span class="p">()</span><span class="w"> </span><span class="o">&lt;&lt;</span><span class="w"> </span><span class="sc">&#39;\n&#39;</span><span class="p">;</span><span class="w">  </span><span class="c1">// false</span>
<span class="p">});</span></pre>
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